Automatic sprinkler systems typically comprise an adequate water supply, hydraulically designed internal piping and sprinklers connected in a systematic pattern over the protected area. The system is activated by a fire to discharge a fine spray of water over the heat affected by a fire.
The essential features of such a system include an inherent ability to detect fire, prior installation, and built-in associated activation means. The automatic sprinkler system is amongst the earliest-used architectural features that contribute actively to maintenance of internal environment.
Automatic sprinklers are the most widely used fixed apparatus for fire protection. The water spray acts four ways:
it cools burning material by conversion of water to steam; PA1 the steam displaces the oxygen supply, thereby tending to smother the fire; PA1 the spray limits the supply of new fuel by dampening materials in the area; and PA1 the spray lowers the temperature in the vicinity by evaporative cooling.
Through prompt response, an automatic sprinkler system generally requires less water to control a fire than does a hose. The vertical spray produces less mechanical damage than does a horizontal hose stream. A sprinkler system is considered effective if it extinguishes or checks a fire until fire-fighting forces arrive. Failure of such systems principally occur when the systems have been rendered inoperative during building alternation or disuse, or the occupancy hazard has been increased beyond initial system capability.
Typically, the water supply for a sprinkler system is separate from that used by a fire department. Normally, no water flows in the supply lines to the sprinklers, thus freezing is a greater risk than in mains with continuous flow. Standards require sprinkler mains to be buried well below the frost line. The underground main enters the building in a heated area to supply a riser.
Connected at the riser are valves, meters, and often an alarm to sound when flow exceeds a predetermined minimum. At the top of the vertical riser, a horizontally disposed array of pipes extends throughout the fire compartment in the building. Other risers feed distribution networks to systems in adjacent fire compartments. Compartmentalization divides a large building horizontally, on a single floor, and vertically, floor to floor. Thus, several sprinkler systems may serve one building.
In the distribution network, branch lines carry the sprinklers. A sprinkler may extend up from a branch line, placing the sprinkler close to the ceiling, or a sprinkler can be below the branch line. For use with concealed piping, a flush-mounted pendant sprinkler extends only slightly below the ceiling.
The principal component of the system is a thermally sensitive sprinkler with a linkage assembly that holds closed the discharge opening. In various designs, the assembly is disrupted through a low-melting point chemical, a frangible bulb filled with liquid, a bimetallic disk, or usually a low-melting-point alloy link. The linkage separates above the operating range which may be any one of a number of standard steps from 100.degree. F. (38.degree. C.) to 475.degree. F. (246.degree. C.). Then, the sprinkler abruptly opens to discharge water against a deflector so that water falls in a hemispherical spray across the area below.
Water reaches the sprinklers in different basic setups. In the usual wet-pipe system, for heated buildings, all pipes contain water under pressure for immediate release through any sprinkler that opens.
In the dry-pipe system which includes pipes, risers, and feed mains which pass through open areas, cold rooms, passageways, or other areas exposed to freezing such as unheated buildings in freezing climates or for cold-storage rooms, branch lines and other distribution pipes contain dry air or nitrogen under pressure. This pressure holds closed a dry pipe valve at the riser. When heat from a fire opens a sprinkler, the air escapes and the dry-pipe valve trips; water enters branch lines; and fire suppression begins.
It will be appreciated that sprinkler systems require means to enable the system to be drained. In the dry-pipe systems, it is the typical practice to provide an auxiliary drain to facilitate the periodic drainage. The auxiliary drain may be located in a riser and positioned at a level to collect water which may become present in the distribution system. In climatic conditions that experience changes in temperature, the piping of a dry-pipe type system may collect condensate that must, from time to time, be drained from the system.
Typically, auxiliary condensate drains are disposed in a riser pipe and have an inlet end in fluid communication with the pipe network of the system and an outlet end in fluid communication with a sewer, for example. The inlet and outlet ends are provided with normally closed one inch (25.4 mm) valves. A fluid reservoir for collecting condensate from the system is disposed between the inlet and outlet valves. The reservoir is formed of a main pipe having a two inch (50 mm) O.D. and length of approximately twelve inches (305 mm). The inlet end of the inlet valve is attached to the outlet of a one inch O.D. riser of the sprinkler system, while the outlet end is coupled to the inlet of a reducer member coupled to the inlet of the main reservoir pipe.
The outlet of the main reservoir riser is coupled to a reducer. The other end of the reducer is coupled to the inlet of the outlet valve. The outlet of the outlet valve is provided with a one inch (25 mm) nipple and cap or plug.
Connections between the valves, reducers, and reservoir are typically threaded-type couplings which are costly to fabricate, time consuming to install and repair, and are subject to leakage.
The object of the present invention is to produce an auxiliary condensate drain for dry-pipe type sprinkler systems that may be economically manufactured, easily installed and readily repaired and maintained.
Another object of the invention is to produce an auxiliary condensate drain for dry-pipe type sprinkler systems that will reduce the number of connections required thereby reducing the potential for leaks to develop.